Sejuani could use a buff that might make her somewhat useful in lane. Her jungle is pretty good, if slow, but it's completely dependent on blue for any sustainability as she's got serious mana issues. That said, her ult and her Q/E combo can make or break games, but I'll be darned if it isn't difficult to be consistent with someone that is completely dependent on blue AND early kills to be effective in early and mid game.

Also everyone quit picking on sejuani, shes a slow jungler, but shes a great solo top, and she can play support tank as well. If you learn how to play her and know your team and base your team fights around her ult you will straight win games.